Some indicators of left ventricular dysfunction in hypertensive patients, depending on the level of matrix metalloproteinases and tissue inhibitors of metalloproteinase-1

Aim. To study the level of matrix metalloproteinases-1 and -2, and tissue inhibitor of metalloproteinases-1, the indicator of left ventricular myocardial deformation in patients with stage 12 hypertension. Methods. 114 patients (40 women and 74 men) with hypertension of 12 stages observed in the cardiology Department of the Road clinical hospital Chita II were examined. The median age was 428.3 years. Left ventriclular diastolic function was studied by using tissue Doppler imaging in apical four-chamber views. Serum matrix metalloproteinase-1, matrix metalloproteinase-2, and tissue inhibitor of metalloproteinases-1 levels were measured in all patients on automated immunoassay analyzers using ready-to-use ELISA kits. Results. An increase in serum levels of matrix metalloproteinases-1 and -2 in the group of patients with hypertension and diastolic dysfunction by 46 and 47%, respectively, was found against increased levels of serum tissue inhibitor of metalloproteinase-1 (р=0.049). In patients with diastole dysfunction, myocardial global longitudinal strain was decreased in was observed by 22.8% compared with patients without diastole dysfunction (p 0.05). The analysis revealed a moderate negative relationship between left ventricular global longitudinal strain and the serum levels of metalloproteinases-2 (r=0.64, p 0.05). Conclusion. In patients with hypertension and left ventricular diastolic dysfunction, a decrease in left ventricular global longitudinal strain is associated with the serum level of matrix metalloproteinase-2; a tissue inhibitor of metalloproteinases-1 is unrelated to left ventricular global myocardial strain.

Biomarkers of persistent renal vulnerability after acute kidney injury recovery

Acute kidney injury (AKI) is a risk factor for new AKI episodes, chronic kidney disease, cardiovascular events and death, as renal repair may be deficient and maladaptive, and activate proinflammatory and profibrotic signals. AKI and AKI recovery definitions are based on changes in plasma creatinine, a parameter mostly associated to glomerular filtration, but largely uncoupled from renal tissue damage. The evolution of structural and functional repair has been incompletely described. We thus aimed at identifying subclinical sequelae persisting after recovery from cisplatin-induced AKI in rats. Compared to controls, after plasma creatinine recovery, post-AKI kidneys showed histological alterations and attendant susceptibility to new AKI episodes. Tubular function (assessed by the furosemide stress test, FST) also remained affected. Lingering parenchymal and functional subclinical alterations were paralleled by tapering, but abnormally high levels of urinary albumin, transferrin, insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinases-2 (TIMP-2) and, especially, the [TIMP-2]*[IGFBP7] product. As subclinical surrogates of incomplete renal recovery, the FST and the urinary [TIMP-2]*[IGFBP7] product provide two potential diagnostic tools to monitor the sequelae and kidney vulnerability after the apparent recovery from AKI.

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) are localized in the nucleus of retinal Müller glial cells and modulated by cytokines and oxidative stress

Matrix metalloproteinases (MMPs) are involved in the pathology of numerous inflammatory retinal degenerations, including retinitis pigmentosa (RP). Our previous work revealed that intravitreal injections with tissue inhibitor of metalloproteinases 1 (TIMP-1) reduce the progression of rod cell death and inhibit cone cell remodeling that involves reactive gliosis in retinal Müller glial cells (MGCs) in rodent models. The underlying cellular and molecular mechanisms of how TIMP-1 functions in the retina remain to be resolved; however, MGCs are involved in structural homeostasis, neuronal cell survival and death. In the present study, MMP-9 and TIMP-1 expression patterns were investigated in a human MGC line (MIO-M1) under inflammatory cytokine (IL-1β and TNF-α) and oxidative stress (H2O2) conditions. First, both IL-1β and TNF-α, but not H2O2, have a mild in vitro pro-survival effect on MIO-M1 cells. Treatment with either cytokine results in the imbalanced secretion of MMP-9 and TIMP-1. H2O2 treatment has little effect on their secretion. The investigation of their intracellular expression led to interesting observations. MMP-9 and TIMP-1 are both expressed, not only in the cytoplasm, but also inside the nucleus. None of the treatments alters the MMP-9 intracellular distribution pattern. In contrast to MMP-9, TIMP-1 is detected as speckles. Intracellular TIMP-1 aggregation forms in the cytoplasmic area with IL-1β treatment. With H2O2 treatments, the cell morphology changes from cobbles to spindle shapes and the nuclei become larger with increases in TIMP-1 speckles in an H2O2 dose-dependent manner. Two TIMP-1 cell surface receptors, low density lipoprotein receptor-related protein-1 (LRP-1) and cluster of differentiation 82 (CD82), are expressed within the nucleus of MIO-M1 cells. Overall, these observations suggest that intracellular TIMP-1 is a target of proinflammatory and oxidative insults in the MGCs. Given the importance of the roles for MGCs in the retina, the functional implication of nuclear TIMP-1 and MMP-9 in MGCs is discussed.

Myeloid-Derived TSP1 (Thrombospondin-1) Contributes to Abdominal Aortic Aneurysm Through Suppressing Tissue Inhibitor of Metalloproteinases-1

Objective: Abdominal aortic aneurysm is characterized by the progressive loss of aortic integrity and accumulation of inflammatory cells primarily macrophages. We previously reported that global deletion of matricellular protein TSP1 (thrombospondin-1) protects mice from aneurysm formation. The objective of the current study is to investigate the cellular and molecular mechanisms underlying TSP1’s action in aneurysm. Approach and Results: Using RNA fluorescent in situ hybridization, we identified macrophages being the major source of TSP1 in human and mouse aneurysmal tissues, accounting for over 70% of cells that actively expressed Thbs1 mRNA. Lack of TSP1 in macrophages decreased solution-based gelatinase activities by elevating TIMP1 (tissue inhibitor of metalloproteinases-1) without affecting the major MMPs (matrix metalloproteinases). Knocking down Timp1 restored the ability of Thbs1 − /− macrophages to invade matrix. Finally, we generated Thbs1 flox/flox mice and crossed them with Lyz2-cre mice. In the CaCl 2 -induced model of abdominal aortic aneurysm, lacking TSP1 in myeloid cells was sufficient to protect mice from aneurysm by reducing macrophage accumulation and preserving aortic integrity. Conclusions: TSP1 contributes to aneurysm pathogenesis, at least in part, by suppressing TIMP1 expression, which subsequently enables inflammatory macrophages to infiltrate vascular tissues.